we all have different reasons for forgetting to breathe
by starlight.moon.princess
Summary: Sherlock had a good reason for not wanting a mate - the last thing he wanted was to be dependent on a boring human, even if it was the only way he could be the consulting detective he always wanted to be. Of course, he hadn't counted on Mycroft. Or John. Vampire!Sherlock AU
1. Chapter 1

**For the Alternate Universes Challenge and the OTP Bootcamp (3. "Don't talk to me") on the BBC Sherlock Fanfiction Challenges forum**

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In another life, he could have been a consulting detective like he had always wanted be. Had biology played out a bit differently, he could have been out solving crimes.

But the universe hated him. It was the only explanation for his situation. He was forced to hide in the shadows, making sure not too draw too much attention to himself, just in case even one of the humans had enough brains to figure out what he was.

_It's for your own good_, Mycroft had said.

As if. All his brother cared about was making sure that the humans never found out that the vampires of their mythology were not, well, mythological. If they ever found out that vampires were not only real, but also roamed freely among them, it could be disastrous.

Well, that was according to Mycroft. Sherlock didn't believe it one bit. Mycroft was a bit of a prima donna, the way he liked to exaggerate things. From what Sherlock had seen of humans over his long lifetime, they would be _thrilled_ by the concept of actual vampires.

They had no sense of self-preservation, humans. They'd throw themselves into the closet dangerous situation just because they could.

They were so _predictable_, so utterly _boring_.

And Mycroft _knew_ that and _still_ insisted Sherlock needed to find a mate among _them_.

_That_ was the true curse of being a vampire. It was easy enough for a vampire to walk in sunlight, to pass so convincingly for a human that not even the most imaginative or intuitive person could tell what they were.

But everything had its price, and the price of humanity was dependence.

Each vampire supposedly had a human who was a perfect, for lack of better word, mate for them. They were the ones who would ground the vampire, make their feral traits easier to control, thereby allowing them to pass for humans. They were everything a vampire needed them to be – a companion, someone to feed from, anything.

But then, that was the problem in itself. Each vampire only had one destined mate in his immortal life. Once the mate had been found, it was an easy enough job to make him immortal to match the vampire. But since there was only one mate for a vampire, the vampire had to make sure that his mate was kept satisfied.

An unsatisfied mate could very easily pack up and leave, abandoning his vampire to his feral nature. And so a vampire was dependant on the whims and fancies of his mate, careful of stepping out of line and losing their partner forever.

Sherlock hated the entire concept. Who in their right mind would be willing to bind themselves so completely to another creature, especially if it was a boring _human_?

But even _he_ grew tired of having five arguments a day on the topic with Mycroft, so here he was, in a human bar, looking for his mate.

At least, that was Mycroft thought. Sherlock was using this outing to freely indulge in one of his favourite pass-times – human watching.

It amused him to end, deducing who and what each person was. Like the man at the bar, who was very obviously married even though he was flirting with every moving female. And the two women near the bathroom. They were second cousins, and obviously madly in love with each other. Not that either of them planned on doing anything about it.

And that handsome man dressed in faded jeans and a soft polo neck – good quality, clinging to his body enough to attract approving attention – chatting up a couple of attractive looking males couldn't be more than twenty-five. No – he had just turned twenty-five, and his friends had brought him here for a celebration. Medical student, graduating soon, and planning to enlist in the army.

For some reason, the thought of that man – whoever he was – getting shot at made Sherlock extremely uncomfortable. The person in front of him was meant to be protected, he couldn't just watch him waltz into-

He let out a barely controlled growl. _Mycroft_. Of _course_ Mycroft had known his bloody _mate_ would be here today – there was no other reason for him to have suggested this particular bar. The next time he met his brother, he was going to-

"Mate, are you okay?" A voice broke through his annoyed thoughts. A voice as soft as butter, perfect and-

_This_ was why he hated the concept of a mate.

He looked down at the man in front him, fighting down his irritation. If he lost control of his vampire side here, Mycroft would never let him live it down.

"Don't you have some more men to flirt with?" he forced out instead, hating himself for being so harsh with his mate. But this was for the best. "Maybe the next one will take your mind off the reality that your sister is a raging alcoholic." And oh, how Sherlock longed to fix that for him. It wouldn't even be that difficult, really…

Damnit, he hadn't anticipated just how strong the instinct to keep his mate happy was. He would just have to push his body a little further then, to make sure it didn't respond visibly to the man.

"How did you-" The man shook his head, an abrupt movement. "Never mind, that's not why I came over here. I was wondering if you were interested in a dance?"

"Do you always proposition complete strangers?" Sherlock threw back at him. He had to stop himself from getting caught up in him…

"Not at all," the man replied easily, flashing him a quick smile. "Just the gorgeous ones like you. By the way, I forgot to tell you – I'm John Watson. What's your name, then?"

_John_. Hebrew origin, meaning God is gracious. A strangely ironic name for the mate Sherlock had never wanted.

_And yet,_ his traitorous heart whispered, _he isn't put off by my deduction. He's the only person I've met who isn't hurt or insulted by them._

_Maybe he truly is my perfect mate._

Sherlock quickly shook himself to clear his head. His thoughts were utterly absurd. The last thing he wanted was to depend on someone.

"My name is Sherlock Holmes," he replied curtly, dismissal obvious in his voice. "And I'm not interested in dancing. Now, if you would kindly find someone else to proposition, I would be most grateful."

"Ah, come on, no need to act like that. It's just one dance."

Obviously, John wasn't about to leave him alone unless he agreed to dance. So Sherlock would accept, and at the end of one song, he'd leave and never see John again.

He would leave London; make sure to stay there until John died. The life of a human was so fleeting to an immortal that he would probably not even notice it.

It was the only way he could think of to make sure he stayed himself.

"Very well," he told the patiently-waiting John. "One dance."

The way John's face lit up in happiness made him want to stay with him, make him happy and keep him content…But Sherlock controlled his body, not the other way around.

At least, that was what he thought. But then they reached the dance floor and John brazenly invaded his space, dancing so close that there was barely any space between them. That, combined with the rhythmic thump of the music blaring from the speakers resulted in some sort of strange hypnotic effect on Sherlock.

All he could focus on was the mesmerizing way John was moving against him, the desperate desire he felt to taste the blood he could see throbbing in the vein on John's neck…it was all he could do not to bite him right there.

Instead, Sherlock settled for burying his face in the little hollow where John's neck met his body, inhaling the delicious scent that was just inherently _John_, only raising his head to glare at anyone who got too close to _his_ mate.

It was only when John pulled him in for a kiss that he realised that he'd somehow gotten in over his head.

Mycroft was going to be unbearable.

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**A bit of an explanation of the vampire universe I've created here:  
**

**Vampires exist without the knowledge of humans, hiding away from attention for fear of their secret being revealed. They function pretty much like traditional vampires - aversion to sunlight, thirst for blood, high aggressiveness etc etc _unless_ they find their mate.**

**The "mate" is a regular human who is perfectly matched for the vampire. Basically, he or she will control the vampire's more animal impulses mainly by providing blood, but also by being a partner. Though the arrangement seems to favour the vampire, it's actually designed to protect the human because a vampire is incapable of harming his/her mate. If the mate is unsatisfied/unhappy and chooses to leave, there is little they can do. So each vampire strives to keep their mate happy constantly. If the mate leaves after the vampire has a taste of a life with his/her mate, the vampire tends to go insane and either go on a killing spree or commit suicide.**

**Because the "mates" are human and mortal, while the vampires are immortal, the vampires have developed a drug that makes the mates immortal without turning them into vampires.**

**Not all mate-vampire bonds are romantic. Most are, however, due to the simple fact that the two of them are perfectly matched.**


	2. Chapter 2

**Due to popular demand, here's a second chapter!**

**For the Alternate Universes Challenge and the OTP Bootcamp (14. Pretend) on the BBC Sherlock Fanfiction Challenges forum**

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"Would you repeat that please?" John asked with forced calm. His plan for the night had been very simple: enjoy his birthday cum going away to Afghanistan party, and find a hot man to spend one of his last nights in England with.

He had thought he'd accomplished that. He really had. Sherlock Holmes was the very picture of perfection, and completely out of his league. Usually, he wouldn't even have attempted to bother coming on to him, but tonight he'd decided to throw caution to the wind. After all, there was no telling if and when he'd be returning to England, so if he was rejected, he wouldn't have to hide in shame for the next few months.

To his utter astonishment, after a bit of coaxing, Sherlock had accepted his offer to dance, and within moments of getting on the dance floor, Sherlock's lips had been on his neck, sucking at his pulse and transporting John to a world of pure pleasure.

He could only faintly remember the events that had followed. Only one moment was crystal clear in his mind – the feel of Sherlock's lips on his own. He remembered that they had been dancing, and Sherlock had gently cupped John's face with his hands and looked deep into his eyes. The everchanging colour of Sherlock's gorgeous eyes had drawn John into their spell, and he remembered his own eyes becoming heavy…and then Sherlock had bent down and kissed him oh so gently. His lips were so soft; his hands wrapped in John's blond mess of hair…John could clearly remember Sherlock's hands lazily stroking his face and jaw…

It had been the most pleasurable and erotic experience John had ever had in his life.

After that, the rest of the night was something of a blur of colours, excitement and happiness. He had never wanted to wake up from the world of two he and Sherlock had created.

But, of course, all good things came to end, which was how he found himself here, wherever here was, listening to a slightly overweight man talk about vampires and mates and other unbelievable things. He had been just about ready to chalk it up to a delusion caused by too much loud music when Sherlock had appeared out of nowhere.

At that moment, he had become convinced he had been kidnapped by a bunch of crazy men and was just about getting ready to scream when the unknown man had _snarled_ at him. The utter and complete transformation he had undergone, from the fangs to the fierce expression on his face, would give John nightmares for months.

Of course, the fact that the man had snarled at him had launched an argument between him and Sherlock, who was apparently mystery man's little brother. Sherlock had said, "He's _mine_, Mycroft! You had no right to attack him like that!"

Before mystery man – Mycroft, his mind amended – could reply, John had decided that it was time for him to get involved in the conversation. After all, they were talking about him.

"What exactly are you two talking about? What do you mean by I'm yours, Sherlock?" he had asked, genuinely curious to see what was going on between the two apparently vampire brothers.

That was when Mycroft had explained everything to him calmly.

Which was what had led to where they were currently.

"So you're saying that I'm expected to just give up my job, my _life_, just because I'm _supposedly_ Sherlock's mate?" John asked furiously.

"You have to understand how valuable mates are to us, John," Mycroft replied calmly. It made John want to drive a stake through his heart. "There is no possible way that you can be allowed to walk into a war zone willingly."

"Allowed? _Allowed_?" John exclaimed, now incredulous. "I'm an adult! You don't have to _allow_ me to do anything, it's my decision whether I want to do it or not!"

"You will find that your name has been removed from all military records, Doctor Watson. You do not have an option – there is no way for you to return to the military." The complete calm in Mycroft Holmes' voice made John wish that he had his gun with him. He would have liked to shoot a few walls to get rid of his aggression at the very least.

"I did not sign up for this, Mr Holmes," he said, forcing himself to remain polite. "The last thing I wish to do with my life is be nothing but the 'mate' of a vampire."

"Doctor Watson-"

"I am not particularly thrilled with this turn of events either, John," Sherlock said, cutting into the conversation between his brother and mate.

"Brilliant!" John exclaimed, seizing onto Sherlock's proclamation like a lifeline. "Can't you tell your brother to stop poking his abnormally large nose into my business and let me go then?"

"I'm afraid I cannot do that no matter how much I would love to," Sherlock replied, sounding truly regretful. "Vampires are genetically hardwired to protect their mates at any cost. There is no possibility of my biology allowing me to let you walk into a war zone."

"Brilliant! What am I supposed to do now?"

"I would advise you to take the "life extending potion," as you insist on calling you, before you decide to do anything else, Doctor," Mycroft said, interrupting the conversation.

John glared at him. "Are you insane? I'm not about to make myself immortal and tie myself to some random man-vampire-_whatever_ I met at a club a couple of hours ago! How do I even know what kind of a person he is? For all I know, taking that potion could mean tying my life to an insane psychopath!"

Before Mycroft could say anything, Sherlock spoke. "I have a suggestion," he said with a mischievous glint in his eye. "Now that I have found my mate – that is to say, found you – I will be able to work as a consulting detective, like I have always hoped to. Mycroft's mate is a DI at New Scotland Yard, and he's agreed to let me work with them. I will need an assistant, however, and you fit the profile of one perfectly."

"What exacting _is_ a consulting detective?" John asked, eyeing Sherlock suspiciously.

"It's who the police approach for help when they're out of their depth – that is to say, always. I will be the only one in the world. I've invented the job myself," Sherlock replied. He could see John was staring to waver, so he decided to up the ante. "It will be rather dangerous," he continued.

The mention of danger was what convinced John. "Very well," he said, "I'll work with you. But I reserve the right to leave if I ever feel that things won't work out."

"Of course, John. But I must add one condition of my own. If, after a year, you feel you can spend eternity by my side, you will agree to become immortal," Sherlock said slyly.

"Done. Can we get out of here now?" John asked eagerly.

"I don't have a better idea. Oh, and I've got myself a flatshare for the…"

Mycroft watched his brother and his mate walk out of the room with something akin to astonishment. The two of them together were going to make for some moments, he could already tell.

He flipped open his phone and spoke imperiously into it. "I think it's time we upgraded my brother's surveillance level," he said, "and while you're at it, add John Watson to the list of people to be monitored. Level three for both of them, I think."

Yes, life was going to get very interesting now that John Watson was among them.

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******As of now, there will not be a full length multi-chapter for this - I just don't think I'm skilled enough to write Sherlock multi-chaps yet.** But it is quite likely that I will be writing more in this universe. I don't know when, but it will happen.

**The only thing is I'll probably be putting them as completely separate fics instead of adding them to this fic. So if you're interested in reading them, you can just put me on author alert. :)**

**Don't forget to drop a review on your way out :)**


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